Adjusting Width

Hey,

I can’t seem to find the search function on the website so I’m not sure if this question has already been asked. Sorry about that! 🙂

I was wondering how I would go about editing the width of the website I’m creating, I’d like to get it looking somewhat similar to the demo in terms of shape. I’ve edited the CSS to pad the body on the left and right, however this doesn’t seem to work too well on different resolutions despite the fact that I’ve used a percentage. It’s also awkward in terms of adjusting the padding for everything else. Is there a better way of going about doing this?

Thanks in advance 🙂
Syk